Mike,A 19x080 gas spring fits nicely in the TF58/QB58. It is one of the easier rifles to convert. A blue label (90 bar) spring makes it a smooth shooter - 10 FPE (7.9gr @ 750fps). I use a red label (130 bar) spring on my TF58. A little harsher but more power. I modified the piston to increase the stroke to 2.95" and use a Teflon oring seal. It puts out about 12.5fpe (7.9gr @ 840fps). Some barrel work and a GRT trigger make it a competitive FT rifle. I'll be shooting mine at the nationals in Oregon this month. My scores are typically middle of the pack against TX200's, R9's, etc.It has an 18 inch barrel. Probably too long for the chamber volume. You can chop 6 inches off the barrel and it becomes a very short rifle. My actual barrel is 10.75 inches but I added a 6 inch long muzzle weight.
tell me about the muzzle brake. Was your gun loud or was the brake for balance?
I went and found the post and I like the looks of it. Nice shooter. Is that a Hammers side-focus scope? Do you recommend it?